Conversion from VBA to VB .NET

Ive got the attached Code which i have converted from Excel VBA
it worked perfectly fine in VBA,
i know that it would need to be converted in some parts. and i have done that.
but it Crashes on in the Function at "GetVersionExA(osinfo)"

one of the awsome things in .net is you have almost everything you need inside the framework and you dont need api calls anymore (which vb and vba needed desperately). though i didnt read trhough all your api calls, i'll bet most if not all of them can be replaced with .net framework's objects

but that's the downside in your case, since you're using so many, it'll take you quite a while to find all the replacements. still, if you decided you want to migrate, i think it will be worthwhile to do it
another approach to it might be moving the code into vb6 and creating an activex dll from it, then call it from .net

The entire process is a formula to check if a Username/Password/Domain combo is valid.
Public Function SSPValidateUser(ByVal User As String, ByVal Domain As String, ByVal Password As String) As Boolean

SSPValidateUser(MyUserName,MYDOMAIN,MyPassword)
i was trying to use it in a Log-in form, so we can use our Windows Logins, rather than remake new Usernames for the users.